The Proportion of Catagen and Telogen Hair Follicles in Occipital Scalp of Male Androgenetic Alopecia Patients: Challenging the Established Dogma.
Level 4 - case-series / case-control
Case series / descriptive ex vivo tissue study in a small surgical cohort.
PubMed 39422326 · doi:10.1111/exd.70001
What was done
Researchers performed ex vivo stereomicroscopic examinations on hundreds of hair follicles harvested from the occipital scalp of 14 Caucasian males during routine hair transplantation surgery to assess the proportion of follicles in catagen versus telogen phases.
What was found
In all 14 patients evaluated, the proportion of catagen follicles was higher than telogen follicles, averaging 7.5% catagen and 3.5% telogen. This contrasts with the established reference values of 1%–2% catagen and 10%–15% telogen.
Why it matters
These findings suggest that standard reference ratios for human hair follicle cycling stages may systematically underestimate catagen frequency, with potential implications for diagnosing and studying hair cycling disorders.
Limits
The study was restricted to a small cohort (14 patients) of only Caucasian males undergoing hair restoration for androgenetic alopecia. Measurements were limited to occipital scalp tissue, and the abstract does not report the total follicle count, anagen percentages, or comparisons to healthy non-alopecic controls.
Cited by
- supports Approximately 90% of human hair is in the anagen phase which can last for years, around 2% is in the catagen phase, and roughly 10% is in the telogen phase.